It has been apparent for sometime that valuable aluminum is being wasted by being discarded with other waste material because the aluminum is not susceptible of easy recovery by the application of magnetic separators. It is recognized that aluminum used in containers is a valuable source of that metal which if recoverable can be recycled so as to reduce the amount of bauxite that is needed in the manufacture of aluminum containers.
The recovery of metal from waste material has been proposed by the use of machines like that disclosed by Vollmer U.S. Pat. Nos. 2,844,184 of July 22, 1958, or by the sorting of scrap metals as disclosed by Anderson et al 2,942,792 of June 28, 1960, or by apparatus of the character disclosed by Williams in patent 3,283,698 of Nov. 8, 1966, and further disclosed by Williams in patent 3,702,682 of Nov. 14, 1972. The main purpose for the apparatus of the prior art has been focused on the recovery of magnetic material, or in the case of the Anderson disclosure of the sorting of aluminum scrap from other metals by a method calling for gravity separation thereof in a water suspension to recover light metal portions from scrap material and melting the recovered light metal by a so called "sweating process" in which an attempt is made to selectively melt the aluminum away from metallic contamination still mixed therewith. By and large, recovery apparatus has operated on the premise that magnetically responsive waste material is economically extracted from a moving stream by passing it adjacent magnetic separating devices and allowing the non-magnetic waste to pass on by.
The disposal of waste materials of all kinds and description in the past have been carried out by dumping in landfill areas and allowing destruction thereof by natural processes. The landfill disposal has worked in a satisfactory manner for materials that will disintegrate in time, but which does not take into account the fact that aluminum does not disintegrate and is therefore a troublesome component of waste. Landfill disposal operations are fast being shut down because it is recognized that some of the waste material contains heat values, because the ferrous metals can be reused, and because the aluminum would be a valuable source for recycling processes if it could be recovered.